Gasolene-operating rock-drilling engine.



R. S. TROTT.

GASOLENE OPERATING ROCK DRILLING ENGINE. APPLIOATION FILED sEPT.4,1aos.

Patented Mar. 16, l1909.

4 SHEETS-SHEET 1.

ii. i l n y gij 4 I 'Rl Si GASOLENE OPERATING BOUK DRILLING ENGINE.

' APPLICATION FILED SEPT. 4, 1906. 91 5,320.

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Patented Mar. 16, 1909 lill? I uumf R. s.TR0TT. GASOLENE OPERATING ROCK DBILLING ENGINE.

APPLICATION FILED SEPT. 4,1906.

Patented Mar. 16, 1909.

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@MQ h R. S. TROTT.. GASOLENE OPERATING ROGK'DRILLING ENGINE.

APPLICATION FILED SEPT. 4,1906. A'

Patented Mar. 16, 1909.

4 SHEETS-SHEET 4.

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/AU W//Q U'Nitrnnsmrns PngrnNT OFFICE.

Y ROLLAND s. 'rao'rfig or DENvEaoLoRADo.

vcuissonsNE-ornm'rrNe nocxmnILLrNG ENGINE.

Specification o! Letters Patent. Application led September 4, 1906. Serial No. 838,279.

Patented March 16, 1909.

To all whom it may concern:

Beit known that l, ROLLAND S. Tno'r'r, a citizen of the`United States of America, re- ,siding in thecity and county of Denver and State' of Colorado, .have invented a new and useful GasoleneeOperating.Rock-Drilling Engine, ofwhich the following is a specification.

My invention relates to gasolene operating' 3,.is a transverse, sectional view taken on the i line 3 3 of Fig. 2. Fig.-4, is a rear elevation of the engine. Fig. 5, is -a longitudinal, horizontal', sectional view, of the cylinder of Y theengine. Fig. 6, is a transverse, vertical, section of the same, on the line 6-6 of Fig. 5. Fig. 7,'is a vfront elevation Aof the engine. Fig. 8, is a` vertical sectional view through the pawl and ratchet mechanism of Fig. 1, on a line with the pawls. Fig.' 9, is a sectional view ofthe ump which is operated by the movement' oi) force waterY through the drill bit. Fig.' 10, is a plan view o fa 'portion of the hammer piston, showing the iston cushioning mechanism` in section. igs. 11 and 12, are respectively, sideA and end views of the Swingin arm, shown in Fig. 10. Fig. 13, is a sectionsJ 'View through the crank shaft, disk, and pin, .J showing the oil passage therein. Fig. 14, is v -a front elevation of the front c linder head;

Fig. 15, is a front elevatori of t e drill hold- 'linguchuck showing the recesses in whichthe .-pawls are journaled; Fig. 16, is .a view of one of the pawls; Fig. 17, is a'vertical, sectional -view through the drillholdingchuck on the dotted lines 17-17 of Fig. v1; Fig. 18,

is a view 'of a portion of the cylinder hood,

showing the air' inlet passages; and Fig. 19,

is a detailed sectional view through the end of the hose nipple and clamping ring.

y Referring .to the drawings, the numeral 1,

designates the cylinder casing of 4my improved drill; 2, the crank shaft casing, and 2A the hub of the crank shaft casing. This re 1, isa vertical, longitudinal, sec-u the hammer piston, to

Similar characters of reference refer 'to' smnlar parts throughout the several views.

. erahk shaft .casing is secured by cap screws 2B above an opening, formed in the top of the cylinder casing; and 3, is the lfront cylinder head, which is bolted tothe front end of the cylinder casing by bolts 4. The cylinder which a sleeve nut 7, is secured, a portion of the nut being turned to fit the aperture of the lug. The nut is provided with a shoulder portion 8,v that fits against one side of the ug, and a threaded'portion 9, upon which a washer 10 is placed, and a nut 11 is screwed on the sleeve 1n position to bolt the sleeve to the lug, the nut being arranged to be screwed against the o posite side ofthe lug from the shoulder. -T e sleeve 7, is interiorly threadwhich is' provided with a crank handle 16, which is removably secured to a reduced shouldered end formed on the screw. The bottom of the cylinder casing is provided with depending slideway lugs 16A, which move in guideways 16, formed in the sides of a su porting shell 16?'. This shell is Y rovided) at its rearend with two rods 16D,w lch extend rearwardsubstantially parallel to the endsare securely bolted to a crossbar 16E, having an a erture centrally positioned between the said bolts,in which the feed screw ad'acent to its crank handle portion is rotata ly mounted. A collar 16F'is` formed on the feed screw, which bears a ainst the inside of the cross-bar, and the cra handle clamping yoke is positioned on the feed screw against the cross-bar on the other side, and actsas a-collar for that side, and the feed bar endof the shell. Y The bottom of the shell clampedto the chuck of a supporting column used to support drills "in the shafts, stopes,

fed 4through the lshell by rotating the feed screw,'wh1ch moves the threaded nut sleeve along as it is rotated.

' he cylinder casing is provided with a cylinder bore 17, in which a piston 1S is reciprorear end withlpacking rings 18A. The' inner periphery of the cylinder is also provided with a packing ring 19, which'is ositioned close to the forward end of the exp osive portion of the cylinder,l and is adapted to preell is provided with a depending lug portion 5, which contains a central aperture 6, 1n

ed to receive a feed screw 13 the rear end of screw is thus rotatably secured at the crossis provided with al depending dove-tailshaped hub l16",-which is adapted-to beaxis of the cylinder, and .at their opposite and tunnels of mines. The'drilling engmeis cally fitted, which is provlded adjacent to its i vent the explosive mixture which enters the cylinder and crank chamber and which is drawn into it through the inlet port 19A and valve 19B, from the carbureter 20, on the back stroke of the piston, from flowing past the pistony into the rear end of 'the cylinder, as will be explained more fully hereinafter. The rear end of the cylinder casing forms the explosive part of the cylinder, and the peripheral surface of this end of the casing is formed into iiuted or ribbed surfaces, or thin projecting circumferential ian es, that form heat radiating surfaces, and a t readed aperture 21 is formed through the axial centerv of the rear end of the c linder, which` receives a plug 22, and througli this plug passes a terminal Wire connectmg plug 23, to which one end of a cicrit wire 24, is attached. This plug 23, 1s made of non-conducting material,

and extends into the interior of the cylinder, a wire or rod passing through it, and extend- -lng beyond its inner end, and a gap sparking wire is connected at one end to the plug 22, and extends adjacent to the end of the plug 23. A binding post 23A'is formed on the outer end of th plug 23, to which the wire 24, is connected at one end, the opposite end of which extends to one fmember'of a termi nal cou ling, which is composed of the parts -23B an 2 3, which are secured to a convenrent portion of the casing, and insulated from 1t and from each other.-A A wire 23D extends from the member 233 of the terminal cou f ling to a brush 23E, which is secured to an a Justable -ring 23F, which is rotatablyseated m a step formed in the upper end of the hub 'of the crank casinl From each member of the'terminal coup ing, extends anl arm 22A, and these arms constitute a clamp, lwhich recelves a battery plug 22B, having wires 22C and 22?, which connect with the oppositepoles of a battery. This plug is inserted in theclam to` operate the engine, and. withdrawn, W enit is desired to stop the engine. A non-conductive interrupter rlng 23G, issecured by a screw 23H, to the hub of a i'lywheel 231, which is mo unted cna crank shaft 23, that is rotatably journaled in the caslng 2, as will be explained hereinafter.

A metal strip 23K'is secured to the interrupter ring 23, by the ,screw 23, and the brush`23E is secured to the'adjustable ring- 23E in position to contact with the terminal strip23x. The brush is insulated from the ring as shown. A finger lever 23L is formed l onv the ring 231", and a shortnotched surface 23M is formed on the langeof the crank casthe Iing can be turned by the lfinger leveru 60.

' at the desired point, of the '65 ing, to hold the linger lever"c'onsequen tly and the brush set and lockedinfany position desired, to contactwith the metal plate of the hub of the fly Wheel to make a spark consequently an explosion at. the spark gap iston s move-v men-t. At .each revolution o the fly wheel the metal strip strikes the brush of the binding post and completes an electric circuitl and spark gap through -the casing to the metal strip, and through the brush and the wire 23D to the cou ling 23C, and through' the wire 22D to the attery. To the lower end of the shaft 23J is secured a crank disk' 3A, having a dependingpin 3B, the object of which will appear later. 4

The front endof'the piston is provided with a projecting-flange plate 25,k which projects into a chamber -2c at the forward end of the cylinder casing and,v below the crank casing, and an integral ba1 "'2D is formed on the piston, rear of the flange 25, which its and moves within the chamber 2C. This chamber extends laterally beyond -each side of the piston chamber, as shown in Figs. 3 and l'6, and in its rear-end adjacent to the sides ofthe chamber are cylindrical holes or bores 2E, which extend through the Wall of the .chamber and into lugs 2F, which are- .formed on the top of the casing. These holes are adapted to receive a pair of thimbles 2G, which are secured to the rear side of the bar 2D of thepiston, and the holes and thimbles form a cushioning medium for the piston on its rear. stroke, as will now be described. Thc thimbles 2G are screwedinto threaded apertures in the rear side of the bar `2", and their rear ends are closed, while their threaded ends are open asfshown in Fig. v10. Aswinging plate 2H`is secured at `one end to the forward side of the bar 2D.

This plate has an apertured lu which extends through an aperture in t e bar', and into the end of one of the thimbles 2G, and is secured by a pin 21. lThe o posite end of this arm has an apertured ug, which extends through an opening in the bar 2D,'con centric with the bore of the other thimble, and to this lug is pivotally secured, by a pin 2J, one end of an arm 2K,"which extends down into thev thimble, and has apiston 2L,

pivoted at its opposite end.- As the hammer iston 18, is driven forward by the explosive ibr'ce of the gas, the fly wheel '231, will be turned by contact' of late 2, with the crank pin 3B, and thevp ate will' notswing entirely out, until about the time the pin passes the center, which is just after the pis- A ton hammer has struck the drill bit. The piston is then moved rearward by the 1mpetus of the whefel,which causes thecrank pin to' contact with the swinging plate', j

which will be thrown back;v its" piston *2L compressing theA air in the thimble and cushlonin the blow of the crank pin, andas the thim les enter the holes 2E, the airv Within will be compressed, and the rear stroke of the piston cushioned. The opposite sides of the mner periphery of the pistons cylinder bore at right angles vent rotation of the piston in its cylindricall bore.

The crank shaft casing includes the liange portion 2, and the hub portion 2^, and is rovided with an axial bore which is rovided with an anti-friction metal bus ling 29, which is flanged to extend across the greater portion of the hub of the crank casing. The shaft 23, which I call the crank shaft, is rotatably mounted in the bushed bore of this crank casing, and extends beyond the outer end of the hub of this casing, and upon its end the ily wheel 23 is secured. The crank shaft extends to the inner end of this casing, and is provided with the disk 3^, which rotates in a circular' recess formed in the end of this crank shaft casing to receive it. A crank pin 3, is secured to the inner face of this crank-disk, and a roller 30, is rotatably 25 secured in any suitable manner to the pin, but preferably by a metal washer 31, and screw 32; the washer being set into a counterbore formed in the other end of the roller, the screw 32 being inserted throughthe 30 washer and threaded into the end of the crank pin. The crank-pin and roller project into the recess, '.between the fixed plate 25, and the swinging plate 2, and it -rotates in contact with the swinging plate. The rear- 35 ward stroke of the piston compresses the explosive gas in the rear end of its cylinder, and consequently exerts an opposing pressure to the rearward stroke'movement of the crankpin The piston is provided with an axial 40 ore of two diameters 44 and .-45. The smaller bore is tapering, and is adapted to receive the rear end of a drill-bit striking bar 46, which I term the hammer bar, and whichis made long enough to project beyond the front end of the piston far enough to enter a spirally fiuted or ril-led sleeve 47, in which it is closely fitted but reciprocally mounted,

and its front end-is arranged and adapted tostrike the shank of -a rock-cutting drill-bit 48, the shank end of which projects loosely in the front end ot said riied sleeve into the reciprocal path of the hammer bar of the` piston. This sleeve is rotatably mounted in anV axial bo're of the front cylinder head, and .projects forwardly beyond it a short distance. A collar portion 49, is formed on its front end, which bears against the bottom of a counterbored axial aperture 50, which is of larger diameter than the axial bore, in which'the sleeve is rotated, and a circulan ratchet toothed terminal end portion 51, extends beyond the collar. The rearV end of this sleeve extends loosely into the larger bore 45, of the piston, which reciprocates on it. In the front face of the bottom of the counter-bore the end of the rifle-bar sleeve.

of the front cylinder head, opposite to the collar 49, I form a circumferential recess 52, in the bottom of which I formfour or Ymore holes extending into the cylinder head, anc in each of these holes I place coiled springs 53. These springs bear against a packing ring 54which is placed in the circumferential recess 52. This packing ring may be of rubber, leather, asbestos, steel, or of any suitable metal, which fits loosely in the entrance of the recess and bears with a resilient pressure against the adjacent face. I employ this packing ring to prevent the escape of theexplosive mixture to the atmos here, through the bearing between the cy inder head and the sleeve and the collar of the sleeve, and thus l,out through the bearing joints of the hub of the front cylinder head and its members to the atmosphere. In the inner face of the wall of the recess, in which the crank disk is seated, I form a circumferential recess 32, in the bottom of which I place expansive coiled springs 33, and in its entrance I place a packing r1ngl34, of any suitable metal or material, whic is adapted to bear against the side of the crank d isk and prevent the explosive mixture from escaping out through the crank s'haft's bearing to the atmosphere.

The axial bore of the hub of the cylinder head is provided with a sleeve 56, the/ inner end of which is provided with a large axial recess 55, which allows the inner end of this sleeve 56 to extend and lapover the ratchet toothed end ofthe rifle bar sleeve and fit rotatably in the main bore of the cylinder head. The recess 55 of the ratchet toothed end is enough larger than the ratchet toothed end of the rifle-bar sleeve to form a space, in which I place ratchet toothed pawls 57, the 'outer sides of which are provided with trunnions which are pivotally journaled in holes formed in the side walls of the bottom wall of the recess 55, of the sleeve 56. The sleeve 56 extends forwardbeyond the frontend of 'the hub portion of the front cylinderhead, a short distance, and 1t is confined in the hub of the cylinder head by a collar 59, the outside surface of which is threaded and fits into a' threaded counter- 11-5 bore in the end of the axial bore or hub of the cylinder head, which its loosely over a reduced portion formed on Vthe sleeve, that terminates in a shoulder Within the hub of the cylinder head, against which the end of the collar abuts, thus confining the head end of the sleeve 56, in the hub of the cylinder head .between the end of this'collar and This sleeve 56, I term the drill-chuck, and it contains an axial bore of the same diameter as theV axial bore of the rilie sleeve, which bores are made to receive loosely the shank ends ofV the rock-cutting dI'ill-bit 48, which extends through Ythe drill chuck and into the rifle 130' sleeve a' short distance.

drill-bit may be of any type of rock-cutting l drill-bits in use. I preferably use a dril This rock-cutting l ing engine through an aperture 75, formed in the front cylinder head, which enters the rear end ofthe bore of' the hub of -thecylinderbit with a round shank', and on the shank head, and intersects an aperture 76 formed in adjacent to its piston striking end I form on f the collar of the rifle sleeve, to the shank of rejecting the drill-bit, in which a transverse aperture diametrical` opposite sides two lugs 58, and the outer end of the rill chuck i 77, is 'formed into its side that/intersects the is provided with oppositely arranged conl drillbits axial aperture, which extends centric recesses 59A, which extend into a portion of its length, and are adapted to receive the projecting lugs 58, of the drill-bit, and

are enough longer than the thickness of the lugs to allow the lugs to be turned rotatably around the axial center of the drill-bit and' a short collar 67, is threaded .to screw into it.

This collar is provided with an axial bore in which the shank of the drill-bit fits loosely,

and on diametrically opposite sides of this collar two radial` slots 68, are vformed, enough larger than the projecting lugs `of the shank to permit these lugs to be pushed easily through them into the recesses 59A. A hole is formed in the inner endjwall of one of the recesses 59A. which extends into the drill chuck substantially parallel with its longitudinal axis, in which one end of a pin 71, projects for a short distance. This is made long enough to extend across the recess 59, and bear at its opposite end against the collar 67, and in the hole 70 I place a coiled expansive spring 72, which is arranged to normally hold the in under resilient pressure against the colar, and in the shell of the drill-chuck above this pin I form a slot 73, through which the lower end of a finger pin 74, which is arranged to slide loosely in the slot, is extended, and is secured to the pin 71. A slot 74A is also formed in the end yof the collar 59, which registers o ver and in permitthev lugs of the drill shank'to beturned past its outer endagainst the wall of the recesses, and past the slots in the collar far enough-to permit the pin bolt to extend past the lug of the drill-bit and bear against the collar, thus locking one of the lugs of the drill-bit between the spring bolt and the farthest wall of the recess, in which the spring bolt is located, and thus locking the drill-bit to the chuck.

l l employ a st rea-n1 of waterfor washing the rock-cuttings from the cut-ting lips of the drill-bit, asholcs are being drilled in rock, and preferably lead the water int-o the drill- .end of the nipple'. A pipe e i through itv from its rock cutting end to near the end of its. shank portion and in order to secure sufficient pressure on this water to force itA through the drill-bit to its rockcutting lips, I employ the following means: In the cylinder head is a threaded aperture 78, which extends partially through the same,l and at the bottom of this aperture an aperture oi' smaller diameter extends through the cylinder head, a shoulder 7 9 being formed at the juncture of the two apertures-see Fig. 9. In the aperture 78, is -sc'rewed' a thimble 80, having a piston 8l, which is limited in its rearward movement by the shoulder 79, and in its forward movement by the inclosed end of the thimble. Two holes 82 and 83, extend from the front end oi the thimble into the chamber in which the piston 81 is located, and nipples 84 and 85 are screwed into these holes. The hole 82 is formed with a valve seat adjacent to its rear end, beyond which the diameter of the hole is necessarily contracted, and' a ball valve 86 moves between the valve seat and the end of the nipple 84. The end of the nipple 85, is formed with a valve seat, and a stop is formed adjacent to the end of the hole 83, which limits the rearward movement of a ball valve 87, which moves between it, and the valve seat in the 84 extends from the nipple 84, to a nipp in the hole 75, of theA cylinder head, and a pipe 85* extends from the nipple 85 to a water supply. Thus the movement of the engine'piston oscillates the piston 81, which draws the water in through the pipe 85^ and forces it out through the pipe 84^ to the drill bit.

The cylinder casing is provided with a projecting hub 81A, in which an inlet aperture 8lA is formed. The entrance to this inlet is threaded, and a nipple 83A is threaded toA it. This ni ple is provided with a yneck ortion, and a s eeve 84 vis rotatably mounted)V on the nipple 83, and a spring catch comprising a finger grasping stem 85, towhich one endV of a spring 86 is attached, the opposite end of which is secured to the sleeve. grasping stem is held by the resilient tension of the spring in a groove 87, formed in the sleeve, which registers over the neck ortion of the nipple 83^, and the stem norma ly projects into this groove and locks the sleeve to the nipple, while permitting the sleeve to rotate freely on the nipple. This sleeve forms the upper end of a hollow yoke or Urshaped v pipe or tube member 88, to the lower end of which a gasolenev carburetor 20 is secured. 130

This carbureter may be of any of the types of carbureters in common use, and it 1s secured to the bottom of a gasolenetank 00, and is` from the carbureter to the inletport. The

gasolene tank is attached to the sleeve by a link 88A, which is pivotally connected between two lugs formed onthe sideof the sleeve. The connection of the sleeve to the nipple permits rotation of the gasolene tank and carbureterV in one direction, and the' link connection at one side of the sleeve permitsl the tank and carbureter to swing in the opposite direction; consequently the gasolene tank and thecarbureter are connected to the cylinder by substantially a universal joint, and are free to swing in all directions. The inlet valve is positioned in the inlet aperture of the hub of the cylinder casing, and normally keeps this passage closed, and is preferably arranged therein in the following manner: A thimble 91A is threaded to an annular band portion formed in the inlet aperture, and a valve seat is' formed on the side -of the ring end of the thimble, and a disk valve 19B is seated against the vale seat. A valve stem projects from this disk valve downward loosely. through anaperture formed through x the bhttom of the thimblc, and far enough below it to'receivey a coiled expansion spring 92, which surrounds the stem, and one end of .which bears against the bottom of the thim ble, and its opposite end bears against a washer which is secured to the endflofrtl'ew valve stem, and this springv by'its expansive force holds the valve disk against the valve seat. of the ring portion of the thimble. Below this valve an aperture is formed, ,in the shell of the hub through which the valve-seat thimble is inserted, and a plug 93 is threaded to this aperture. A port 94 extends'through l the shell of the cylinder from the'rear end bf the cylinder to the crank disk and piston chamber, and it is positioned in the rear cylinder at a point where it will be onlyuncovered at about the endA of the forward stroke of the piston, andit is positioned in the crank chamber at a4 point where the forward stroke of the piston will compress the explosive gas,` and force it through this port to the rear end of the piston and cylinder, where on the rearward stroke f the piston it is compressed in the rear end of the' cylinder.

The cylinder casing is provided with an exhaust outlet aperture 98, which is formed in the shell of the casing oppositeto the gas' inlet port 94j This exhaust outlet exhausts into a-hood 99, which I form laround the rear end of the cylinder casing, which may be 'the `exhaust outlet of the hood, an exhaust hoseni ple 102 is attached Where it connects to the ood, as it is-necessary to frequently detach the hose from the hood in order to reset the drilling engine. The hose nip le is connected to thehub of the hood by lifeing detachably clamped thereto, and is preferably clainlped thereto by a clamping collar 103, whic i is provided with inclined slot recesses 104, on its opposite sides, that hook under projecting lu s 105, formed on the op osite side of the ex aust outlets hub of the ood. These recesses are inclined to form a wedge surface that bears against the underside of the lugs when the collar is turned to clamp the nipple and hood together. The end of the hose nipple is flanged, as shown at X, and anintroverted ring Y is formed on the top edge of the collar that lits over the flange, and the collar, when turned onto the lugs of the hub of the hood, clamps the hose nipple to the hub.

Av washer 106 is inserted between the end of theA hose nipple, and the hub of the hood, to prevent leakage of the exhaust or as from the nipple and hood. This exhaust hoseand nipple are used to convey the exhaust gas from the drillinor en ine,.andf.roml.the.shaft, A t un:nelfsieociit-lgi?r mine Working where as ventilates can be reciprocatedl once or twice by a suitable starting crank (not shown), fitting the ratchet teeth on the hub of thelly wheel, and turning it, the roller bearing against the starting plate and pushing the piston forward, and as thev iston reciprocates on its back stroke forced ackby the roller against the Swingin plate, it draws by suction a supply ofexp osive gas from the carbureter throughthe gas inlet valve into the crank chamber in front of the piston, and on tlie-v pistons forward stroke this gas is compressed enough to be forced through the inlet port into the rear end of the cylinder the instant the piston on its forward stroke uncovers the rear end of the port, and in order to prevent the gas from flowing across the cylinder and out of the exhaust port, a deflecting ring or crank-pin andits roller, to permit of a drillthe pistondashes forward it forces `and conrthe explosion of the gas the swinging plate baflie plate Z is secured to the rear end of the piston, which is adapted to defiect the gas and guide it to the lrear end of the cylinder the instant thegas inlet port and the exhaust port are open, as the piston only travels a slight distance beyond them, and almost instantly starts back on its rearward stroke, and covers them, and the gas that is forced is made to flow into the rear end of the cylinder by the forward stroke of the piston, and is com ressed in the cylinder by the back stro e, and the electric spark apparatus is so timed that the metal contact strip on the hub of' the fly-wheel engages the brush of the contact terminal and makes a circuit through the electric wires and the battery herein described, that produces an electric s ark at thes'park gap within the cylinder at its rear end thatY ignitcs and explodes the gas just after the crankin has passed its center, thus driving an( impinging the piston forward and its hammer bar against the shank end of the drill-bit; and as the piston moves forward it uncovers the exhaust port of the cylinder and the gas exhausts into the hood, andA into the exhaust hose, which is directly over the cylinders exhaust outlet port, from which it iiows away from the drilling engine, and out of the mine workings to the atmosphere, and the cold air from the mine workings is sucked into the hood through its air f inlets and around thecylinder by the exhaust, and cools the cylinder and ventilates the mine workings. The hood in a large l measure stiies and mufiies the noise of the explosion and of the exhaust, and it remeves the obnoxious fumes from the minejworking's and thus prevents annoyance and ossible sickness of the operators `,of the'dril ing en gine, from breathing them. y' I The space between the fixed late 2,5, and the swmging plate 2, on t e piston, is enough greater than the diameter of the bit striking com ensating movement suflicient to permit t e piston to travel ahead of the roller crank-pm ,and strike ,its blow against the end `of the drill-shank before the crank pin reaches its forward center and as presses another charge 'of gas to the rear end of the cylinder. vAt the time the explosion `of the gas takes, place, the roller crank-pin which rotates in the' direction of the arrow, has passed itsrear center onits up-stroke, and when the piston is thrown forward by gradually moves out as the crank pin moves away from it, Vand when the crank pinpasses its center on the forward stroke of the piston, it contacts withthe swinging plate, and throws the piston rearward, the contact of the crank pin with the plate; and the rearward movement of the piston, being cushioned in the manner previously mentioned,

it being understood that the fly-wheel is revolved by the contact ofthe swinging plate with the crank pin when the explosion takes place, and the momentum of the wheel causes the crankpin to engage the swinging plate,-when the pin has passed its center,

i and throw the piston rearward. The space between the fixed plate 25 and theswinging plate 2 of the piston, is sufficient to allow the hammer bar of the piston to strike the end of the drill-bit at any part of the drillbits movement in its chuck;` except .that should the piston be operated when the drill-bit is not in operative rock-drilling position against a rock, thestrokes of the piston are taken by the roller crank-pin, as in an engine running free, and this would-also be the Icase when a drill-bit was not in thc chuck. This arrangement prevents the piston striking the front cylinder head, and also from driving the lugs of the drill-bit repeat-- edly against the end f isk of the chuck.V The axial movement of the drill-bit in the chuck is sufficient tol allow the op'erator to feed the drilling engine by the feed screw, as fast as the drill cuts into rock', and to allow thev .drill-bit a feeding movement independent of rock, but the forward feed movement of the enginev should be as near the feed of the drill-bit into the rock under the blows of the piston,-1asit can be regulated by the operator of the engine. Ast I e piston reciprocates the spiral flutes or its axial bore reciprocate on the spiral rifle ribs of the sleeve, which is rotated on the forward stroke of the piston, but on the backward stroke of the piston the ratchet teeth of the sleeve engage the pawls, and as the piston is held from turning by its guides and guide-ways, the pawls anfLdriIlbit holding chuck, and consequently the drill-bit, are rotated an amount equalto the spiral pitch of the riied ribs and iutesA in the piston rod'on the Surface of the rifie sleeve. At e'aeh backward strokeof the piston, it

. cushions on the buffer which as above stated,

maybe a rubber or a pneumatic buer, or spring` steel.

\ The crank-pin roller and crank shaft.,` are preferably lubricatedby an oil passage '108, which isformed axially-through the crank shaft, and then through the crank disk into and ,out throughythe side of the crank pin. The entrance to thisoil passage may be provided with any suitable oil cup, or may be closed' 'by a plug 109. The plston may be oiled from a grease cup 110, which is threaded t'o anoil passage 111,which leads through -v the casing into the hammer pistons cylinder.

While' I have illustrated and described the- .preferred arrangement and construction of my improved `gasolene engine, I dotnot wish i crank disk on the inner end of said crank `ceive the rearward strokes of the swinging vllugs, and thus cushion the rear stro e of the to be limited to it, as there are many changes that might be made without departing from the spirlt of my invention; and while I have l preferably described the piston actuating explosive gas as that fof gasolene, my invention contemplates the use of any other explosive gas suitable for this purpose.

' Having described my invention, what I claim as new and desire to secure by Letters Patent is:

`1. In a gas explosion operated rock-drilling engine, the combination with the cylinder and the piston, of a crank casing connected to said cylinder, a crank shaft rotatably mounted in said casing, a crank-pin on the inner ond of said crank shaft, a projecting fixed plate on the front end of the piston, a swinging plate in the rear of said fixed plate and arranged in bearing contact with said crank pin, cushioning means arranged to rei l I l plate, and means for cushioning the rearward stroke of the piston.

2. Ina gas explosion rock-drilling engine, the combination with the cylinder, of a piston mounted to'reciprocate therein, means for driving said piston on the forward strokes of its reciprocal movements, a fixed lateon the, front of said piston, a swinging p ate pivotally hinged to said piston infthe rear of said fixed plate, a crank shaft journaled in said cylinder, a iiy wheel at one endyof said crank shaft, and a crank pin at its opposite end, and in rotative bearing contact with said swinging plate.

3. In a gas explosion operated rock-drilling engine, a cylmder, a crank chamber adjacent to said cylinder, apertured lugs at the rear end .of said crank chamber, a piston mounted to reciprocate in said cylinder, having thimbles adapted to enter said a ertured plston, a swinging plate on said piston cushloned at one end wlthin one of sald thimbles, a i'ixedplate adjacent to the swinging plate, and a y wheel having a crank pin adapted to move between said xed and swinging plates.

4..In a gas explosion operatedl rock-drilling engine', the combination with a cylinder having a crank chamber, anda piston provided with a swin ing buffer plate and a fixed plate, of a crank s aft in said crank chamber,

a fly-wheel on the outer end of'said shaft,a

shaftin said crank chamber, a crank pin secured to said crank disk and extending bem tween 'said fixed and swinging plates, and I stroke of the piston.

6. In a rock-drilling engine of the character described, the combination with a cylinder having cylindrical apertures, closed at one end, of a piston'having thimbles, which -areadapted to, enter said apertures, an outwardly-swinging plate on said piston cushioned at, one end in one of said thimbles, a iixed late on the iston adjacent the swing,-A irg p ate, a fly wiieel and a crank pin connected therewith and adapted to be engaged bythe swinging plate, on the forward movement of the piston, to revolve the iiy wheel, and to engage thel swinging plate through the momentum ofthe wheelto move the piston rearward. i y

7. In arock-drilling engine of the character described, the combina-tion with the cylinder and piston, said piston Iadapted to` be thrown forward by the explosion of a gas, of means for accomplishing the rearward stroke ofV the piston and of cushioning the said stroke, said means comprisin an integral bar on said iston, and thimb es secured to said integral) bar,cylindrical air pockets in said cylinder, which said thimbles are adapted to enter, an outwardly swin ing lplate pivoted at one end to the integral ar,

and having a piston adapted to move in the thimble at the oppositeend of the bar, /a fly j n pin connected therewith Wheel, and a cra and adapted to be' engaged by -the swinging plate to' revolve the fly wheel, as the plston shoots forward, and to engage said swlngin plate through'the momentum of the flywheel, k to throw the ,piston rearward, f

In testimony whereof I afx' my signature presence of two witnesses. l p ROLLAND s.1 TRoT'r.

" Witnesses: I 1

l ,G. SQ ELLIOTT,

ADELLA M. FowLE..5 

